Modeling of Mutual Coupling Between Electromagnetic and Thermal Fields in Microwave Heating

This paper presents the analysis and modeling of the mutual coupling between thermal and electromagnetic fields. During the microwave heating process the microwaves are dissipated to heat due to the dielectric losses of the medium. The heat propagation inside the medium depends on its thermal parameters as well as on different propagation mechanisms. In most cases the dielectric properties are dependent on the temperature. In this paper a model is described for a microwave assisted soil decontamination system. The dielectric properties of the soil not only depend on temperature but also on the moisture content which reduces during the heating process. With changing dielectric properties of the soil the electromagnetic field distribution changes as well which again has an influence of the heat propagation. The basic principles of microwave heating and heat propagation are explained in this paper, as well as a simulation model based on an FEM code. To prove the correctness of the model a comparison with measurement results is given.